1. Field of the Invention
The present invention relates to cycle trainers and particularly to a cycle trainer by which training can be done indoors, simulating real outdoor riding.
2. Description of the Background Art
There have been developed various cycle trainers used for cycle training in a room, simulating real outdoor running, in which a bicycle not having a front wheel is fixed and the rear wheel of the bicycle is rotatably in contact with a rotating roller to which load is applied.
FIG. 17 is a schematic side view of such a cycle trainer disclosed in U.S. Pat. No. 4,441,705, and FIG. 18 is a sectional view taken along the line XVIII--XVIII of FIG. 17.
Referring to those figures, the structure and functions of the cycle trainer will be described.
A bicycle from which the front wheel is removed is fixedly supported by a front frame 152 and a stay 156 by means of a front fork 16 and a bracket lug 154. The front frame 152 is connected to a support 150 which is a main body of the trainer, and a height adjusting portion 158 into which the stay 156 is inserted for adjustment of the height is attached to a central portion of the support 150. A stable setting member 151 in the form of a pipe perpendicular to the support 150, for stably setting the trainer is connected to an end of the support 150. A load applying device 1 on which a rear wheel 10 is mounted is attached to a portion of the support 150 near the stable setting member 151 through an adjusting bolt-nut set 164. The load applying device 1 comprises a roller 26 having a high friction coefficient to be in contact with a tire 44 of the rear wheel 10, a rotating shaft 162 inserted integrally in the roller 26 and rotatably supported by a support frame 30, a fan 50 attached to an end of the rotating shaft 162, and an inertial wheel adjuster 166 attached to the other end of the rotating shaft 162. The fan 50 is covered with a casing 51, which has an opening connected with an air tube 160 having a top end near a handle portion of the bicycle.
When the trainer is to be used, the height of the stay 156 is adjusted by the height adjusting portion 158 according to the size of the bicycle to be fixed and the bracket lug 154 is attached to the stay 156. Then, the adjusting bolt-nut set 164 is adjusted to move the support frame 30 forward or backward so that the tire 44 is in contact with the roller 26, and then the load applying device 1 is fixed by fastening the adjusting bolt-nut set 164. After the adjustment and fixation of the bicycle, the user rides on the bicycle and practices cycle training by means of pedals 14 in the same manner as in real riding of a bicycle. The pedal movement rotates the rear wheel 10 and rotates the roller 26 through the tire 44. The rotation of the roller 26 rotates simultaneously the fan 50 and the inertial wheel adjuster 166 through the rotating shaft 162. The inertial wheel adjuster 166 serves to apply a riding resistance in real riding to the user and the inertial wheel can be replaced at any time with other inertial wheel of a different size or weight. The fan 50 serves to apply an air resistance in real riding to the user and it gives a resistance to the rotating shaft 162 according to rotation of the roller 26, that is, a real riding speed. A quantity of air generated by the rotation of the fan 50 is made to blow from the front side to the user of the trainer through the air tube 160 so as to produce an effect as if in outdoor riding of a bicycle.
In the above described conventional cycle trainer, it is difficult to precisely simulate a real riding resistance.
More specifically, although the inertial wheel adjuster 166 and the fan 50 are provided to simulate the riding resistance and the air resistance in real riding of a bicycle, those devices exhibit their functions only on the basis of accurate contact between the tire 44 and the roller 26. However, the adjustment of the contact depends on adjustment by using the height adjusting portion 158 and the adjusting bolt-nut set 164 and therefore accurate adjustment of contact force cannot be expected. Thus, the resistance applied to the rotating shaft 162 by means of the inertial wheel adjuster 166 and the fan 50 cannot be accurately transmitted to the crank of the pedals 14 through the roller 26 under the tire 44 and accurate stable workload cannot be given to the user in a satisfactory manner.